Normally, younger relatives would take care of the inmates once they're released. But in some cases the costs (and loneliness) are simply too much to bear in a troubled economy, and seniors look to prison as the better alternative.

Employees are succumbing to 'death from overwork.'

Long work hours are leading to a rise in cases of karoshi, or "death from overwork."

A report from October, which examined karoshi and its cause of death, found more than 20% of people in a survey of 10,000 said they worked at least 80 hours of overtime a month — a signal of just how desperate young people are for extra income.

Japan's government is taking steps to encourage people to leave work on time or take off one day entirely.